People often think of Christian morality as a kind of bargain in which God says, "If you keep a lot of rules, I'll reward you, and if you don't I'll do the other thing." I do not think that is the best way of looking at it. I would much rather say that every time you make a choice you are turning the central part of you, the part that chooses, into something a little different from what it was before. And taking your life as a whole, with all your innumerable choices, all your life long you are slowly turning this central thing either into a Heaven creature or into a hellish creature: either into a creature that is in harmony with God, and with other creatures, and with itself, or else into one that is in a state of war and hatred with God, and with its fellow creatures, and with itself. To be the one kind of creature is Heaven: that is joy, and peace, and knowledge, and power. To be the other means madness, horror, idiocy, rage, impotence, and eternal loneliness. Each of us at each moment is progressing to the one state or the other.

-C. S. Lewis, taken from The Joyful Christian

As a side note, I'd like to add that the progress toward either rarely looks like much of an epic battle of decisions. 'The line dividing good and evil cuts through the heart of every human being.' It's an unremarkable line with remarkable consequences. Let no one fool you; the progress toward hellishness is a gently sloping downhill ride in the calm of mid-afternoon. The progress toward Heaven is narrow and riddled with innumerable annoyances and seemingly unnecessary sacrifices. It will seem irrational and inconsequential, but take the harder way.